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Heterologous expression analyses of rice OsCAS in Arabidopsis and in yeast provide evidence for its roles in cyanide detoxification rather than in cysteine synthesis in vivo

While most dicot plants produce little ethylene in their vegetative stage, many monocots such as rice liberate a relatively large amount of ethylene with cyanide as a co-product in their seedling stage when etiolated. One of the known functions of β-cyanoalanine synthase (CAS) is to detoxify the co-...

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Autores principales: Lai, Kwok Wai, Yau, Chi Ping, Tse, Yu Chung, Jiang, Liwen, Yip, Wing Kin
Formato: Texto
Lenguaje:English
Publicado: Oxford University Press 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2652057/
https://www.ncbi.nlm.nih.gov/pubmed/19181864
http://dx.doi.org/10.1093/jxb/ern343
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author Lai, Kwok Wai
Yau, Chi Ping
Tse, Yu Chung
Jiang, Liwen
Yip, Wing Kin
author_facet Lai, Kwok Wai
Yau, Chi Ping
Tse, Yu Chung
Jiang, Liwen
Yip, Wing Kin
author_sort Lai, Kwok Wai
collection PubMed
description While most dicot plants produce little ethylene in their vegetative stage, many monocots such as rice liberate a relatively large amount of ethylene with cyanide as a co-product in their seedling stage when etiolated. One of the known functions of β-cyanoalanine synthase (CAS) is to detoxify the co-product cyanide during ethylene biosynthesis in higher plants. Based on a tryptic peptide sequence obtained from a partially purified CAS activity protein preparation in etiolated rice seedlings, the full-length putative rice CAS-encoding cDNA sequence (OsCAS), which is homologous to those O-acetylserine sulphydrylase (OASS) genes, was cloned. Unlike most of the CAS genes reported from dicots, the transcription of OsCAS is promoted by auxins but suppressed by ethylene. To address the function and the subcellular localization of this gene product in planta, a binary vector construct consisting of this gene appended with a yellow fluorescent protein-encoding sequence was employed to transform Arabidopsis. Specific activities on CAS and OASS of the purified recombinant protein from transgenic Arabidopsis were 181.04 μmol H(2)S mg(−1) protein min(−1) and 0.92 μmol Cys mg(−1) protein min(−1), respectively, indicating that OsCAS favours CAS activity. The subcellular localization of OsCAS was found mostly in the mitochondria by immunogold electron-microscopy. Chemical cross-linking and in-gel assay on a heterodimer composed of functional and non-functional mutants in a yeast expression system on OsCAS suggested that OsCAS functions as a homodimer, similar to that of OASS. Despite the structural similarity of OsCAS with OASS, it has also been confirmed that OsCAS could not interact with serine-acetyltransferase, indicating that OsCAS mainly functions in cyanide detoxification.
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spelling pubmed-26520572009-04-02 Heterologous expression analyses of rice OsCAS in Arabidopsis and in yeast provide evidence for its roles in cyanide detoxification rather than in cysteine synthesis in vivo Lai, Kwok Wai Yau, Chi Ping Tse, Yu Chung Jiang, Liwen Yip, Wing Kin J Exp Bot Research Papers While most dicot plants produce little ethylene in their vegetative stage, many monocots such as rice liberate a relatively large amount of ethylene with cyanide as a co-product in their seedling stage when etiolated. One of the known functions of β-cyanoalanine synthase (CAS) is to detoxify the co-product cyanide during ethylene biosynthesis in higher plants. Based on a tryptic peptide sequence obtained from a partially purified CAS activity protein preparation in etiolated rice seedlings, the full-length putative rice CAS-encoding cDNA sequence (OsCAS), which is homologous to those O-acetylserine sulphydrylase (OASS) genes, was cloned. Unlike most of the CAS genes reported from dicots, the transcription of OsCAS is promoted by auxins but suppressed by ethylene. To address the function and the subcellular localization of this gene product in planta, a binary vector construct consisting of this gene appended with a yellow fluorescent protein-encoding sequence was employed to transform Arabidopsis. Specific activities on CAS and OASS of the purified recombinant protein from transgenic Arabidopsis were 181.04 μmol H(2)S mg(−1) protein min(−1) and 0.92 μmol Cys mg(−1) protein min(−1), respectively, indicating that OsCAS favours CAS activity. The subcellular localization of OsCAS was found mostly in the mitochondria by immunogold electron-microscopy. Chemical cross-linking and in-gel assay on a heterodimer composed of functional and non-functional mutants in a yeast expression system on OsCAS suggested that OsCAS functions as a homodimer, similar to that of OASS. Despite the structural similarity of OsCAS with OASS, it has also been confirmed that OsCAS could not interact with serine-acetyltransferase, indicating that OsCAS mainly functions in cyanide detoxification. Oxford University Press 2009-03 2009-01-30 /pmc/articles/PMC2652057/ /pubmed/19181864 http://dx.doi.org/10.1093/jxb/ern343 Text en © 2009 The Author(s). This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited. This paper is available online free of all access charges (see http://jxb.oxfordjournals.org/open_access.html for further details)
spellingShingle Research Papers
Lai, Kwok Wai
Yau, Chi Ping
Tse, Yu Chung
Jiang, Liwen
Yip, Wing Kin
Heterologous expression analyses of rice OsCAS in Arabidopsis and in yeast provide evidence for its roles in cyanide detoxification rather than in cysteine synthesis in vivo
title Heterologous expression analyses of rice OsCAS in Arabidopsis and in yeast provide evidence for its roles in cyanide detoxification rather than in cysteine synthesis in vivo
title_full Heterologous expression analyses of rice OsCAS in Arabidopsis and in yeast provide evidence for its roles in cyanide detoxification rather than in cysteine synthesis in vivo
title_fullStr Heterologous expression analyses of rice OsCAS in Arabidopsis and in yeast provide evidence for its roles in cyanide detoxification rather than in cysteine synthesis in vivo
title_full_unstemmed Heterologous expression analyses of rice OsCAS in Arabidopsis and in yeast provide evidence for its roles in cyanide detoxification rather than in cysteine synthesis in vivo
title_short Heterologous expression analyses of rice OsCAS in Arabidopsis and in yeast provide evidence for its roles in cyanide detoxification rather than in cysteine synthesis in vivo
title_sort heterologous expression analyses of rice oscas in arabidopsis and in yeast provide evidence for its roles in cyanide detoxification rather than in cysteine synthesis in vivo
topic Research Papers
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2652057/
https://www.ncbi.nlm.nih.gov/pubmed/19181864
http://dx.doi.org/10.1093/jxb/ern343
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